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GeographyMediumAsked in: SSC CGL · 13 April 2022, Shift 2

The salinity of ocean waters is calculated as the amount of salt (in gm) dissolved in _____ gm of seawater.

  1. A.10,000
  2. B.100
  3. C.1000
  4. D.10

Correct answer

C. 1000

Explanation

The correct answer is C, 1000. Salinity is the quantity of dissolved salt, in grams, present in one thousand grams of sea water, so it is read as parts per thousand. The average salinity of the oceans is about thirty five parts per thousand, which means about thirty five grams of salt in a kilogram of sea water. Sodium chloride makes up the largest share of it, followed by magnesium chloride, magnesium sulphate and calcium sulphate. Salinity rises where evaporation is high and the inflow of fresh water is low, which is why the Red Sea reaches about forty one parts per thousand, and it falls near the mouths of large rivers and in polar waters fed by melting ice. A, B and D are wrong because a base of ten thousand, a hundred or ten grams would not give the parts per thousand figure that oceanographers actually use. Exam tip: salinity is grams of salt per 1000 grams of sea water, and the ocean average is about 35 parts per thousand.

Practice Questions

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Q2.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements is/are correct? 1. Himalayan rivers have their origin in the snow-covered areas, hence are dry in winter season. 2. Rivers of the Peninsular Plateau have reached maturity. 3. Himalayan rivers depict all the three stages of normal cycle of erosion. Select the correct answer using the code given below.

  1. A.2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: C. 2 and 3 only

Himalayan rivers are perennial, so statement 1 is wrong, while statements 2 and 3 are correct. Himalayan rivers such as the Ganga, Indus and Brahmaputra rise from glaciers and snowfields and also get monsoon rain, so they flow all year round, including in winter.

Q3.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements related to latitude are true? 1. Rainfall, temperature and vegetation vary with latitude. 2. The difference between the longest day and the shortest day increases with latitude. 3. Indira Point is located approximately at 6°45' N latitude. Select the correct answer using the code given below.

  1. A.1 and 2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: D. 1, 2 and 3

All three statements about latitude are true. Latitude decides how directly the Sun's rays strike a place, so temperature, rainfall and the type of vegetation change from the equator towards the poles, from hot, wet rainforests to cold tundra.

Q4.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following lakes is/are situated in Ladakh? 1. Tso Kar 2. Pangong Tso 3. Tsomgo 4. Tso Moriri Select the correct answer using the code given below.

  1. A.1 only
  2. B.2 and 3
  3. C.1, 2 and 4
  4. D.2 and 4 only
Show answer
Correct answer: C. 1, 2 and 4

Tso Kar, Pangong Tso and Tso Moriri are high-altitude lakes of Ladakh, while Tsomgo lies in Sikkim. Pangong Tso, at about 4,350 metres, is a long, narrow lake that stretches from Ladakh into Tibet, and most of its length lies on the Chinese side.